1. Field of the Invention
This present invention relates to enabling off-board voice-enabled real-time turn-by-turn navigation solutions for mobile devices, which typically are wireless devices, where the mobile device has information about its position on the planet. This invention provides the ability to obtain route snapshots from a remote client and/or server system, the cache and reuse of audio navigation voice prompts for network efficiency, and the ability to transmit location (i.e., GPS) history to a remote client and/or server system for the purpose of obtaining highly accurate real-time turn-by-turn voice prompted directions.
2. Description of the Related Art
Navigational devices are typically defined as devices that provide a unit's local position and a way of planning a course around the unit's local position, sometimes to a remote position, as in the case of an in-vehicle navigational device, also well known in the art. Typically, an in-vehicle navigation device consists of a display screen, processing unit, storage unit, and user input mechanism. The storage system typically contains, for example, maps and travel information used for navigational purposes. Travel information may include such POIs as local restaurants, theaters, municipality locations, and the like. Next generation wireless navigation devices, which typically run on cellular phones, need to execute in a resource limited environment, such as a small display screen, reduced processing unit, limited storage unit, and a limited user input mechanism. As wireless navigation devices become ubiquitous they will be required to function as well as in-vehicle navigation devices, while having significant resource restrictions. Some of these restrictions include a single sensor GPS receiver vs. the in-vehicle navigation device which typically includes a high sensitivity GPS device and complementary sensors known as dead-reckoning to those that are skilled in the art.
Determining one's position using a navigational device has typically been accomplished by integrating or connecting a Global Positioning System (GPS) device with various types of computing devices, such as a personal computer or handheld GPS unit. New positioning determination systems include network-assisted wireless location systems, such as Time-of-Arrival (TOA), and network-assisted GPS systems for determining the navigational device's position. The unit's location is then displayed on the device and is available for various applications, such as in the case of a commuter seeking the shortest route to a location in a specific area or a user wanting to find the nearest gas station.
Additionally, map programs are well known in the art, which provide a graphical representation of a set of geographical coordinates, such as streets and highways. These map programs can also be purchased with geocoded POI information, such as restaurants and movie theaters. Current map programs provide search capability for finding the desired POI information nearest to a given inputted geographical coordinate information, such as an address of a house, and getting driving directions to said location.
Wireless device software applications typically require communicating with other remote clients and/or server systems for the purpose of augmenting the capability of the local software application which typically runs in a resource limited environment, such as having a reduced amount of memory compared to personal computers, etc. Adding the ability to navigate on a wireless device requires that the software application obtain as much supplemental route information from a remote server as required to correctly construct the entire route. This is typically denoted to those skilled in the art as off-board navigation. Since the wireless software navigation device has many resource limitations, it is not capable of locally storing all of the necessary map data for calculating routes within a standard city radius. A problem exists since the device can not store all of the map data, it must obtain it from a remote device over the wireless channel. An additional problem exists since the wireless device has limited memory and navigation voice pronunciations are a highly desired feature of a navigation device (i.e., Turn Right on Lawrence Road). Due to the wireless device resource limitations, synthesizing voice data in real-time on the wireless device is typically not feasible due to the constrained memory conditions of the device. Thus, the device requires getting the voice data from the server. As people skilled in the art will appreciate, the wireless channel is typically also bandwidth limited and has a much higher cost per bit pricing when compared to the prior art Internet-based ISP (Internet Server Provider) pricing models.
Since wireless devices are inherently mobile in nature and typically only have a single GPS sensor solution, when compared to dead-reckoning system as present in almost all automotive in-vehicle systems, it becomes extremely difficult to determine where the device was previously located. Additionally, adding both GPS inaccuracies and map vector data inaccuracies, determining your initial starting route point becomes exceedingly difficult from a GPS fix as people skilled in the art will appreciate.
Thus, a need exists for a method and system that can optimize the capabilities of a mobile device for the purpose of enabling the mobile device to perform better than prior art in-vehicle navigation systems. This invention enables the mobile device to function and outperform prior art navigational systems that incorporate real-time voice prompted turn-by-turn directions and without the need of dead-reckoning and multiple sensors. This is accomplished by the combination of the server-client model.